In case you run into an issue, it might be necessary to get more details about the cause of the problem. Therefore, we make use of WordPress’ debug logging.
Now you have to reproduce the issue to get the log entry created.
Therefore, simply do what you did before when the problem occurred: For instance visit your WordPress dashboard/frontend and simply repeat the operation or refresh the page that isn’t working properly.
The actual debug log is saved in a file called debug.log in your site’s wp-content directory.
One way to view and clear your log is to access that file directly via FTP. Alternatively, you can use a plugin like Log Viewer and access the log directly via your admin dashboard.